1. Field of Invention
This invention relates to the field of marine vessels and more particularly to the field of boats using hydrofoils for the purpose of raising a portion or all of the null of the boat free of the water. This invention pertains more particularly to the field of manually powered boats or sail boats having a propulsion source, such as a manually powered or electrically powered propulsion system.
2. Prior Art
Hydrofoil lifting surfaces designed to apply a lifting force to the hull of a marine vessel are known in the art. Such hydrofoil surfaces have either a fixed angle of attack, or an angle of attack that is adjusted by a control system within the marine vessel.
U.S. Pat. No. 3,762,353 titled "High Speed Sail Boat" issued Oct. 2, 1973 and having the same inventor as the subject invention characterizes a sail boat using a hydrofoil on an outrigger flotation means to provide a counter heeling force to keep the sailboat upright. FIG. 9 of the U.S. Pat. No. 3,762,353 patent shows a fixed horizontal foil to lift the stern portion of the hull out of the water to reduce drag. A planing surface arrangement is shown mounted on the bow that is lowered by the operator; however, no provision is shown for pivoting the bow foil apparatus on a yaw pivot axis.
U.S. Pat. No. 3,747,549 titled "High Speed Sailboat" issued July 24, 1973 and having the same inventor as the subject invention is similar to U.S. Pat. No. 3,762,353 but fails to show a horizontal separation of the second pivot point from the yaw pivot at the gooseneck.
U.S. Pat. No. 3,762,353 cites three reference patents which include U.S. Pat. No. 3,286,673 titled "Hydrofoil Stabilizing Means For Watercraft" issued Nov. 22, 1966 to H. W. Nason. This patent shows a hydrofoil used to stabilize a sailboat in roll but does not teach a planing surface sensor arrangement for controlling the hydrofoil angle of attack and no first and second pivot points and no bow attachment assembly is shown on a yaw pivot axis.
U.S. Pat. No. 3,112,725 titled "Sailboat" issued Dec. 3, 1963 to Leroy Malrose shows no submerged hydrofoil.
U.S. Pat. No. 2,139,303 titled "Watercraft" issued Dec. 6, 1938 to W. Grunberg, and Dit Greg shows a vessel supported out of the water on submerged hydrofoils placed behind the center of mass, stationary floats being positioned at its bow. No provision is made for a forward vertical fin, for first and second pivot points nor for pivoting the bow on a yaw axis.